If you run promotions (especially ongoing ones) that mention specific prices and/or promoitional periods, then make sure that when the "deal" changes that you update your ad copy.
I've been getting some ads on Facebook for a fairly interesting looking digital product, clearly in some kind of funnel as I've gone from seeing full price to increasingly aggressive offers.
The product was advertised as having a time limited offer on, for $37 down from $100.
I clicked and added the product to the cart. It then came up as $80 down from $117, but the promotional text refers to getting the $37 deal (limited until end May 2020!)
Long story short, I'm left confused about the actual price/deal on offer.
Don't get caught out with this kind of mistake on your ads if you are displaying prices/specials!